Annoying missfire question, any ideas?

["jamesrguk" <James_rg@xxxx>]

Hi all,

I am still having an annoying misfire, I am pretty sure it down to an 
injector that is passed it's sell by date, as it is not spraying very 
nicely. 

To my knowledge the spray pattern on a mechanical injection system is 
more crucial than on an EFI system because the valves are not always 
open at the point of injection.

I am fairly sure the misfire is fuel related for the following 
reasons:

1) My timing light suggests that all plugs are sparking
2) All plugs are less then 8 months old. 
3) 2 of the injectors are new, 4 are 2nd user but appeared to be 
clean and ok when 1st installed approx. 10 months ago, and the engine 
has run fine until recently.
4) All of my HT leads are new as well as the cap and rotor arm.

Anyway my question is really why are the injectors getting blocked?, 
have I just been unlucky?
I have a new fuel pump, clean tank, and a filter on the fuel pickup 
and had the main fuel filter change about 10 months ago.

Any ideas?


James RG